<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div {
      border: 1px solid #000;
      /*w100*/
      width: 100px;
      /*h100*/
      height: 100px;
      /*m10*/
      margin: 10px;
      /*p10*/
      padding: 10px;
      /*bgc*/
      background-color: #ccc;
      /*fs16*/
      font-size: 16px;
      /*lh2*/
      line-height: 2;
      /*ff*/
      font-family: Arial, Helvetica, sans-serif;
      /*fwb*/
      font-weight: bold;
      /*tal*/
      text-align: left;
      /*bd1#cs*/
      border: 1px #cccccc solid;
      /*bdr5*/
      border-radius: 5px;
      /*bs*/
      box-shadow: 0px 0px 5px #cccccc;
      /*dib*/
      display: inline-block;
      /*posa*/
      position: absolute;
      /*z1*/
      z-index: 1;
      /*tac*/
      text-align: center;
    }
  </style>
</head>
<body>
<!--  #box+.main-->
  <div class="box"></div>
  <div id="main"></div>

<!--ul>li.item{列表元素$}*5-->
  <ul>
    <li class="item">列表元素1</li>
    <li class="item">列表元素2</li>
    <li class="item">列表元素3</li>
    <li class="item">列表元素4</li>
    <li class="item">列表元素5</li>
  </ul>

</body>
</html>